In recent years, infrared modules and Web cameras are used as methods for grasping crowd conditions of facilities. For example, in a facility such as a restaurant, infrared modules are installed at entrances/exits and, e.g., the number of times of blocking of infrared light is counted to estimate the number of people staying in the facility, or a plurality of Web cameras are installed at entrances/exits, moving or still images taken by the cameras are analyzed to estimate the number of people staying in the facility (see, for example, Patent Literature 1 indicated below).